1. Field of the Invention
The present invention relates to camera controllers and teleconferencing systems, and more particularly, to a camera controller for controlling an imaging range of a camera provided with a driver for changing its viewing direction and a teleconferencing system having the camera controller.
2. Description of the Related Art
Recently, teleconferencing systems enabling multipoint conferences by transmitting and receiving voice and video data via a plurality of terminals placed at remote points have been receiving attention. This type of teleconferencing system has a camera having the function of changing its viewing direction and a camera controller for electronically controlling the viewing direction of the camera so as to image a speaker and transmit the obtained image signal to remote terminals.
When a participant in a conference starts to speak, the camera controller controls the viewing direction of the camera so that the speaker can be imaged by the camera. For example, the camera controller predicts a direction from which voices have emanated (hereinafter referred to as a voice direction) via a microphone for capturing voices and causes the camera to automatically pan toward the voice direction. Subsequently, the camera controller detects the contour of the speaker's face, and controls the tilt direction and zoom adjustment of the camera so that the face can be placed at the center of a screen. Thus, the speaker can be imaged by the camera.
A camera direction automatic controller for causing a camera to automatically track an earphone microphone with a lighted lamp has been proposed (see, for example, Japanese Unexamined Patent Application Publication No. 9-307870, paragraphs [0016] to [0030] and FIG. 1). Upon capturing the voice of a speaker, the earphone microphone with a lamp lights its lamp. All participants in a conference wear these earphone microphones. The camera direction automatic controller detects the position of an earphone microphone with a lighted lamp on the basis of image data transmitted from the camera and directs the camera toward the earphone microphone with a lighted lamp.